Battery test rig

ABSTRACT

The present invention relates to a battery test rig, comprising a test cell ( 3 ) in which a battery ( 2 ) to be tested is arranged, a holder ( 13 ) which is arranged in the test cell ( 3 ) and is able to hold the battery ( 2 ), a regulation unit ( 4 ) which can be connected to a battery ( 2 ) arranged in the holder ( 13 ), at least one sensor device ( 5, 6 ) for monitoring the battery ( 2 ), wherein the sensor device ( 5, 6 ) is connected to the regulation unit ( 4 ), and a cooling apparatus ( 7 ), which is connected to the regulation unit ( 4 ) and is designed to cool the battery ( 2 ) in the test cell ( 3 ) from the outside in a hazard situation.

BACKGROUND OF THE INVENTION

The present invention relates to a battery test rig which is used toexamine or check different batteries.

The function and load limits of batteries are checked, for example, aspart of development and production. However, a considerable potentialhazard may result in this case. In particular, in the case of excessivecharging or discharging or else in the case of other externalenvironmental influences, for example a temperature increase, gaseouscleavage products, which may result in a pressure increase, may beproduced in the event of reactions between the existing batterymaterials (cathode, anode, electrolyte). Furthermore, exothermicreactions may entail a further supply of heat. Consequently, the batterymay be destroyed by an explosion. As a result, work on battery test rigsmay be hazardous. It would therefore be desirable to have an improvedlevel of safety, in particular, for the employees working with batterytest rigs.

SUMMARY OF THE INVENTION

In contrast, the battery test rig according to the invention has theadvantage that it is possible to test or examine batteries with anincreased level of safety. According to the invention, high-efficiencycooling can be carried out in this case if necessary. This is achieved,according to the invention, by virtue of the fact that the battery testrig comprises a cooling apparatus which is connected to a regulationunit. A sensor device is connected to the regulation unit in order tomonitor the battery. If the regulation unit detects that there is ahazard situation, it activates the cooling apparatus in order to coolthe battery in order to thus prevent a critical battery state. Theinventive external cooling of the battery thus makes it possible, on theone hand, to reduce a temperature of the battery and a pressure insidethe battery, with the result that a critical situation can be avoided.The inventive use of the cooling apparatus also makes it possible tosafely check research samples of batteries, in particular.

The cooling apparatus preferably comprises a pressure vessel which isconnected to a test cell, in which the battery is arranged, via a line.The cooling apparatus also comprises a switching valve which isconnected to the regulation unit and is opened in a hazard situation inorder to lead a cooling medium stored in the pressure vessel to thebattery. As a result, a large area of the battery may be wetted with thecoolant, thus resulting in a high degree of cooling efficiency. Thepressure vessel may also have a large supply of cooling medium in orderto be able to cool the battery for as long as possible.

The cooling apparatus more preferably comprises a nozzle which isarranged in the test cell and makes it possible for the cooling mediumto expand in the vicinity of the battery. In this case, the coolingmedium is sprayed onto the battery via the nozzle in order to cool thebattery over as large an area as possible. In this case, the nozzle ispreferably arranged above the battery, such that the cooling mediumflows down along the outer periphery of the battery. In this case, thebattery is more preferably arranged horizontally in the test cell, withthe result that as large an area as possible can be wetted with coolingmedium.

According to another preferred refinement of the present invention, thecooling apparatus comprises at least one Peltier unit which is arrangedin the test center in order to cool the battery. The Peltier unitsconsist of Peltier elements which are placed flat against one another,the Peltier elements consisting, for example, of two semiconductorceramics which are connected by metal bridges. If a safety-criticalstate of the battery to be checked occurs, the Peltier unit isenergized, as a result of which one of the semiconductor ceramics iscooled, whereas the other is heated. In this case, the cooling apparatusparticularly preferably comprises a multiplicity of Peltier units whichare arranged in the form of a pyramid. This makes it possible to achievea plurality of cooling stages, such that even large temperaturedifferences of up to 70 Kelvin and temperatures below 0° C. can beachieved. In this case, the last stage of the multiplicity of Peltierunits is preferably connected to a heat exchanger which transports thewaste heat from the test cell.

The sensor device preferably comprises a temperature sensor and/or apressure sensor and/or a force sensor, in particular a strain gage,and/or a distance sensor. In this case, the sensors are preferablyarranged on an outer side of the battery. As a result, a simplestructure of the battery test rig is achieved and, in particular, amultiplicity of batteries can be checked in a short time. It is notedthat a plurality of different sensors are particularly preferablyarranged on the battery. Alternatively, it is naturally also possible toarrange a plurality of identical sensors on a battery to be examined.

The battery test rig preferably also comprises a suction apparatus inorder to suction gases or other media from the interior of the testcell. On the one hand, this results in toxic gases, for example, beingable to be safely suctioned from the test cell and, on the other hand,avoids a disproportionate pressure increase inside the test cell. Avacuum can also be generated in the test cell as a result.

According to another preferred refinement of the present invention, thebattery test rig also comprises a current interruption device, with theresult that yet another safety device is present in addition to thecooling apparatus. In a critical state of the battery to be examined, abattery current is interrupted using the current interruption device inorder to avoid further function-related heating of the battery.

In this case, the battery test rig according to the invention can beused, on the one hand, in research and development departments, whichexamine batteries, and may furthermore likewise also be used by batterymanufacturers for quality control of the batteries produced. In thiscase, the battery test rig according to the invention does not have anyrestriction in terms of the battery to be checked. In particular,research samples, half-cells (electrochemical samples), battery packs,which are composed of modules and have high power levels, or elselithium ion batteries can also be checked.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention are described in detailbelow with reference to the accompanying drawing, in which:

FIG. 1 shows a diagrammatic view of a battery test rig according to afirst exemplary embodiment of the invention, and

FIG. 2 shows a diagrammatic view of a battery test rig according to asecond exemplary embodiment of the invention.

DETAILED DESCRIPTION

A battery test rig 1 according to one preferred exemplary embodiment ofthe invention is described in detail below with reference to FIG. 1.

As can be seen from FIG. 1, the battery test rig 1 comprises a test cell3 in which a battery 2 to be checked is arranged. In this case, thebattery 2 is held in a holder 13 which comprises a plurality of narrowcarriers. The use of the narrow carriers makes it possible, inparticular, to avoid the test results being distorted by thermal loads.Furthermore, good accessibility to the battery 2 to be checked can beensured.

The battery test rig 1 also comprises a regulation unit 4 and a coolingapparatus 7. A pressure sensor 5 and a temperature sensor 6 are alsoprovided and are fixed to an outer side of the battery 2. The pressuresensor 5 and the temperature sensor 6 are connected to the regulationunit 4 via lines 5 a and 6 a. In this case, the reference symbol 2 adenotes an electrical connection between the battery 2 and theregulation unit 4. The cooling apparatus 7 comprises a pressure vessel 8in which a cooling medium 9 is arranged under pressure. The pressurevessel 8 is connected to an interior of the test cell 3 via a line 10.In this case, a switching valve 11 which is in the form of a shut-offvalve and releases or closes the line 10 is arranged in the line 10. Ascan be seen from FIG. 1, the switching valve 11 is likewise connected tothe regulation unit 4 via a line 11 a. A nozzle 12 is also arranged atthe end of the line 10 in order to spray the cooling medium 9 suppliedwhen the switching valve 11 is open. As can be seen from FIG. 1, thenozzle 12 has in this case a width B which is greater than a length L ofthe battery 2. The nozzle 12 is arranged above the battery 2, with theresult that the battery 2 is sprayed with coolant from above and thecoolant can then flow or run down on the outer side of the battery. Thiseffectively also cools central and lower regions of the battery 2.

The reference symbol 14 also denotes a suction apparatus for suctioninggases and/or liquids from the test cell 3 and for generating a vacuum inthe test cell.

The operation of the battery test rig 1 in an emergency is as follows inthis case. The sensors 5, 6 continuously detect, at predeterminedintervals, corresponding sensor values which are supplied to theregulation unit 4. The regulation unit 4 checks the supplied sensorvalues, for example by means of a comparison with stored values. As soonas a sensor value reaches a predetermined threshold value, theregulation unit 4 determines that there is an emergency and activatesthe cooling apparatus 7. For this purpose, the switching valve 11 isopened, with the result that the cooling medium 9 can be passed to thenozzle 12 via the line 10. As a result of the sudden expansion of thecooling medium at the nozzle 12, the cooling medium cools and issupplied to the outer side of the battery 2. In this case, it is notedthat the cooling medium may be a gas or else a liquid. The suctionapparatus 14 is preferably also activated at the same time in order toincrease the cooling efficiency by reducing the pressure in the testcell 3. It is also noted that it is possible to monitor not only thebattery directly but also a pressure inside the test cell 3, forexample. Sensors for measuring a force acting on a battery housing bydevelopment of a gas inside the battery can also be provided, forexample, which sensors may be fitted to the outer side of the battery 2,for example in the form of strain gages. Alternatively or additionally,expansion of the battery can also be detected in a contactless manner,for example using distance sensors, for example via battery angulation.

A battery test rig with an increased level of safety can therefore beprovided according to the invention by the cooling apparatus 7. As aresult, critical situations can be detected by the regulation unit 4when checking batteries and the battery can be cooled using the coolingapparatus 7 or a pressure can be reduced in order to avoid a hazardsituation. It is noted in this case that a plurality of coolingapparatuses 7 may naturally also be arranged in order to have redundancyin an emergency. A plurality of cooling apparatuses may also be used tocool a plurality of regions of the battery 2. For example, additionalnozzles may be arranged laterally or on the end faces of the battery 2.In this case, the nozzles may be supplied via only one pressure vessel 8or alternatively may also be respectively supplied with cooling mediumvia separate pressure vessels.

A battery test rig 1 according to a second exemplary embodiment of theinvention is described in detail below with reference to FIG. 2. In thiscase, identical or functionally identical parts are denoted using thesame reference symbols as in the first exemplary embodiment.

In contrast to the first exemplary embodiment, the battery test rig 1 inthe second exemplary embodiment comprises two cooling apparatuses. Likein the first exemplary embodiment, a first cooling apparatus 7 is formedwith a pressure vessel 8, a line 10, a switching valve 11 and a nozzle12. A second cooling apparatus 17 which comprises a multiplicity ofPeltier units 18 and a heat exchanger 19 is also provided. The heatexchanger 19 is arranged in the housing of the test cell 3 and isconnected, by its inwardly directed side, to the Peltier units 18. Inthis case, the Peltier units 18 are constructed in the form of a pyramidand each comprise Peltier elements which are respectively placed flatagainst one another. The structure in the form of a pyramid results in amulti-stage cooling system, the last stage being connected to the heatexchanger 19. In the exemplary embodiment shown, the second coolingapparatus 17 is connected to one end of the battery 2. Alternatively,however, it is also possible for the second cooling apparatus 17 to onlybe connected to the battery in an emergency. This can be achieved, forexample, in such a manner that the second cooling apparatus 17 isarranged on a linear supply arrangement and, if an emergency isdetected, the second cooling apparatus 17 is moved linearly until it isin contact with the battery 2 in order to dissipate heat from thebattery. Otherwise, this exemplary embodiment corresponds to the firstexemplary embodiment, and so reference can be made to the descriptiongiven there. It is also noted in this case that only a heat exchangerwith a liquid medium or a second cooling apparatus with a cold airstream would alternatively also be possible as the second coolingapparatus. In contrast, however, the use of the Peltier units as thesecond cooling apparatus 17 has the advantage of a small installationspace and a very effective cooling option.

It is also noted that the battery test rig may additionally alsocomprise a current interruption device in order to interrupt a currentgenerated by the battery 2 in an emergency. This ensures that noadditional heat is generated by operating the battery 2.

1. A battery test rig comprising: a test cell (3) in which a battery (2)to be tested is arranged, a holder (13) which is arranged in the testcell (3) and is able to hold the battery (2), a regulation unit (4)which can be connected to a battery (2) arranged in the holder (13), atleast one sensor device (5, 6) for monitoring the battery (2), thesensor device (5, 6) being connected to the regulation unit (4), and acooling apparatus (7) which is connected to the regulation unit (4) andis designed to cool the battery (2) in the test cell (3) from theoutside in a hazard situation.
 2. The battery test rig as claimed inclaim 1, characterized in that the cooling apparatus (7) comprises apressure vessel (8), which is filled with cooling medium and isconnected to the test cell (3) via a line (10), and a switching valve(11) which is connected to the regulation unit, the switching valve (11)being arranged in the line (10) and being able to be opened and closedusing the regulation unit (4) in order to lead cooling medium to thebattery (2).
 3. The battery test rig as claimed in claim 2,characterized in that the cooling apparatus (7) also comprises a nozzle(12) which is arranged in the test cell (3) in order to lead the coolingmedium to the battery (2).
 4. The battery test rig as claimed in claim1, characterized in that the cooling apparatus comprises at least onePeltier unit (18) which is arranged in the test cell (3) in order tocool the battery (2).
 5. The battery test rig as claimed in claim 4,characterized by a multiplicity of Peltier units (18) which are arrangedin the form of a pyramid.
 6. The battery test rig as claimed in claim 4,characterized in that the cooling apparatus also comprises a heatexchanger (19) which is connected to the Peltier unit (18) in order totransfer heat from the Peltier unit (18) to an outer side of the testcell (3).
 7. The battery test rig as claimed in claim 1, characterizedin that the sensor device comprises at least one of a temperature sensor(6), a pressure sensor (5), and a force sensor.
 8. The battery test rigas claimed in claim 1, also comprising a suction apparatus (14) in orderto suction medium from the test cell (3).
 9. The battery test rig asclaimed in claim 1, also comprising a current interruption device inorder to interrupt a current generated by the battery.
 10. The batterytest rig as claimed in claim 1, comprising at least one first coolingapparatus (7) and one second cooling apparatus (17).
 11. The batterytest rig as claimed in claim 1, characterized in that the sensor devicecomprises a temperature sensor (6).
 12. The battery test rig as claimedin claim 1, characterized in that the sensor device comprises a pressuresensor (5).
 13. The battery test rig as claimed in claim 1,characterized in that the sensor device comprises a force sensor. 14.The battery test rig as claimed in claim 13, characterized in that theforce sensor is at least one of a strain gage and a distance sensor. 15.The battery test rig as claimed in claim 13, characterized in that theforce sensor is a strain gage.
 16. The battery test rig as claimed inclaim 13, characterized in that the force sensor is a distance sensor.17. The battery test rig as claimed in claim 1, also comprising asuction apparatus (14) in order to generate a vacuum in the test cell(3).